In recent years, medicine has advanced to the extent that more and more highly developed implantable devices have been developed for treating a wide variety of physical conditions, and to support various body functions. Many of these therapeutic devices are operated with electric power and/or introduce this power directly into body tissue for treatment and/or support of body functions.
To make these devices interactive, implantable sensors and/or actuators that are in constant connection with the device are used, as known from U.S. Pat. No. 6,802,811 B1, for example. The sensors can monitor heart activity or blood flow, for example, while the actuators stimulate certain nerves or organs in the body.
Many implants are remotely operable, i.e., they can be externally activated, controlled, and/or queried regarding their influence on the body, and can remotely supply information about the patient's condition. There are a number of established systems, as well as extensive literature, for implementation of this remote effect (telemetry).
WO 02/056761 discloses a system wherein information about the condition of the implantable device, as well as information about the measured values detected by a sensor connected to the device, is transmitted by ultrasound to an external monitoring unit. The acoustic energy may also be used to store energy in the implantable device. Such a system allows continuous monitoring of the patient, while at the same time avoiding additional surgical procedures to replace the battery on the device, for example. The sensors and/or actuators are interactive elements at the site of the implant, but they are not remotely operable and instead are connected to the implantable device by electric lines.
An implantable device usually includes a housing, which holds the electronic controls, capacitors and batteries. To connect the electric lines from the sensors and/or actuators to the device, a wire or another conductive structure passes through the housing for each pole. With the usually metallic implant housings, each wire passing through the housing must be insulated. However, there is always a galvanic connection between the inside and the environment of the implant.
DE 10 2006 003 224 A1 discloses an implantable device including a connection body that is attached to the housing and has at least one electric connection, but usually two to four electric connections, arranged in one or more externally accessible cavities of the connection body, with the connections being used to connect one or more electrode lines.
Such feedthroughs are critical components with respect to the imperviousness and mechanical stability of the implants. The reason for this is the mechanical connection between the metal housing and the feedthrough which is often made of ceramic. Furthermore, the manufacturing complexity is great and assembly of the feedthroughs is very complex. A galvanic connection through the housing wall also increases the susceptibility of the implant to electromagnetic alternating fields, in particular when a long electrically conducting structure is connected outside of the implant.